PHOENIX (AP) -- NFL owners approved two rule changes Tuesday to enhance player safety. They might not vote on a proposal to ban offensive players from using the crown of their helmets against defenders.

The owners outlawed peel-back blocks anywhere on the field; previously, they were illegal only inside the tackle box. A player makes a peel-back block when he is moving toward his goal line, approaches an opponent from behind or the side, and makes contact below the waist.